calculate the percent recovery for the analysis of a spike. the sample was spiked with 5.00 ml of a 200.0 mg/l solution. the sample matrix concentration was determined to be 30.0 mg/L. The sample matrix volume (excluding the spike) was 90.00 ml. The resulting spike sample concentration was 38.1 mg/l.

percent recovery =( mass in spiked sample – mass in unspike matrix / mass add) times a 100